1. Technical Field of the Invention
This invention relates to a process for preparing and improving the physical properties of formed particles. Particularly, this invention relates to a process for preparing formed particles by adding at least one surfactant to one or more particle components prior to drying the particles.
2. Description of the Background Art
Particles for use in fluid bed reactors, sieves, and other industrial applications are formed by numerous processes. The objective of the particular process for forming the particles is to obtain particles of uniform size and density with a minimum of fines and with desirable physical characteristics. Desirable physical characteristics include low attrition rates wherein the integrity of the particles resists breakage during use in a fluid bed or similar operation.
U.S. Pat. Nos. 4,946,814 and 5,135,756 to Shi et al. disclose a process for improving the physical and catalytic properties of a fluid cracking catalyst. These patents are primarily directed to preparing particles for fluid cracking catalysts because of the commercial significance of such particles. However, the extension of the use of the processes of these patents for forming other particles is disclosed. For example, it is explained in the '756 patent that the basic process can be adapted to form particles for non-catalytic or separation-type materials. In particular, it is disclosed that particles used in binding ceramics and superconducting formulations are improved by the basic process. These particles are typically based on a variety of inorganic oxide systems. The present application continues in part from the disclosures of these patents and hereby incorporates these patents by reference.
U.S. Pat. No. 5,254,516 to Gupta et al. discloses fluidizable zinc titanate materials with high chemical reactivity and attrition resistance. The particles disclosed by this patent are formed from inorganic oxides. Specifically, the particles are formed from zinc oxide and titanium dioxide and can include an inorganic binder which is desirably one of the clays, bentonite or kaolinite. The particles of this patent are formed by a granulator. The disclosed wet granulation procedures are undesirable because of their "batch mode" of operation and their production of particles having less than desired attrition rates. The disclosure of this patent that is related to the compositions of fluidizable zinc titanate materials is herein incorporated by reference.
The industry lacks an efficient and economical process for producing formed particles, such as those particles used in fluid bed reactors, which are microspheroidal without a significant presence of "blow-holes" or cavernous openings and which have desirable attrition rates.